Loading…
Loading…
SigmaCalc
The standard measure of association in case-control studies, comparing odds rather than raw risk.
Odds ratio compares the ratio of odds (event ÷ non-event) between groups, while relative risk compares raw probabilities directly. They converge for rare events but diverge substantially when the event is common — odds ratio is standard for case-control studies where relative risk can't be directly estimated.
An odds ratio of 1 means no association between exposure and the event. Above 1 means the exposed group has higher odds of the event; below 1 means lower odds — how far from 1 indicates the strength of the association.
Odds ratio
3.857
OR = (a × d) ÷ (b × c)
What you entered
Odds of the event in the exposed group
30 ÷ 70= 0.4286Odds of the event in the unexposed group
10 ÷ 90= 0.1111Odds ratio
(30 × 90) ÷ (70 × 10)= 3.8571Result
Odds ratio: 3.857
An odds ratio of 3.857 means the odds of the event are 3.86× higher in the exposed group compared to the unexposed group.